In the past non-woven polyester fiber devices have been placed inside waterbed mattresses to dampen wave motion therein. Such non-woven polyester fiber products suffer the disadvantage that the fiber products have a specific gravity greater than 1.0 and sink in water. For advantageous use of such fiber products, floatation devices such as closed cell foams are used to float the composite structure. The floatation devices typically have reduced the extent to which the overall batt can be compressed for shipment in a minimum of space, have increased the overall mass of the wave damping device, and have generally complicated the process of manufacturing the wave damping devices. Moreover, use of closed cell foam floatation devices have made the waterbed mattresses less comfortable to sleep on in that stiff foam can be felt through the mattress.